The invention relates to a capacitance diode having a semiconductor body with an epitaxial layer of a first conductivity type in which a doping profile is formed by controlled doping during growth, and a surface zone of the second conductivity type in the epitaxial layer which forms a p-n junction with the first-mentioned zone.
When such capacitance diodes are used as tuning capacitances in parallel oscillatory circuits, the resonance curve of the oscillatory circuit is distorted due to the nonlinear characteristic of the diode.
This effect is described in "Valvo Berichte", part VII, No. 2, pp. 97-107, (in particular pp. 99-101). From this article it appears that upon driving the capacitance diode a deviation about the resonant frequency f of .DELTA.f/f occurs in the oscillatory circuit for a voltage variation .DELTA.U across the diode.
In a prior art capacitance diode this disturbing frequency deviation assumes comparatively large and--which is particularly disturbing--both positive and negative values.